generic: Check the fs after each FUA writes

Basic test case which triggers fsstress with dm-log-writes, and then
check the fs after each FUA writes.
With needed infrastructure and special handlers for journal based fs.

[Eryu: cap $nr_cpu to 8 to avoid wasting time on hosts with many cpus]

Signed-off-by: Qu Wenruo <wqu@suse.com>
Reviewed-by: Eryu Guan <guaneryu@gmail.com>
Signed-off-by: Eryu Guan <guaneryu@gmail.com>
4 files changed